Chair control and support

ABSTRACT

An improved tilt control and support mechanism for a chair seat assembly utilizing a simplified sturdy construction wherein a single plate-like element functions to support the seat assembly and, in cooperation with an adjustable compression spring, yieldably restrains the tilt movement of the chair seat in a uniform and controlled manner to permit the occupant to bring the chair seat to a comfortable tilted rest position and return it to a substantially horizontal position.

United States Patent Engstrom 51 Apr. 18, 1972 541 CHAIR CONTROL ANDSUPPORT 3,119,430 1/1964 Di Rico ..85/35 3,185,429 5/1965 Meinhardt [72]Inventor: Carl J. Engstrom, Mlchlgan C1ty, Ind. 3,448,466 6/1969naldopoulosun [73] Ass1gnee: lnterroyal Corporation, New York, NY.FOREIGN PATENTS OR APPLICATIONS [22] 639,350 5/1962 Italy ..248/381 [211App]. No.: 857,922

Primary Examiner-James T. McCall 52] us. 01 ..297/302, 248/381 k Fever[51] Int. Cl ..A47c 3/00 57 ABSTRACT [58] Field of Search ..297/300,301, 302, 303, 304;

4 3 1 379 3 0; 35 35 An improved t1lt control and support mechanism fora chair seat assembly utilizing a simplified sturdy construction [56]References m wherein a single plate-like element functions to supportthe seat assembly and, in cooperation with an adjustable compres- UNITEDSTATES PATENTS sion spring, yieldably restrains the tilt movement of thechair seat in a uniform and controlled manner to permit the occu-804,658 1 1/1 905 Hasfmgs "297/302 X pant to bring the chair seat to acomfortable tilted rest position 1,474,977 1 1/1 923 Mesmger et 31% xand return it to a substantially horizontal position. 1,696,154 12/1928Bump ..248/380 2,729,273 1/l956 Hamilton et al. ..248/379 6 Claims, 7Drawing Figures PATENTEUAPR 18 I972 SHEET 1 [1F 2 FIG. 2.

, INVLN/UR CARL ENGSTROM PMENTEDAPR 18 m2 3. 656.805

SHEET 2 of 2 F l G- INVEN'IOR.

CARL ENGSTROM Arm CHAIR CONTROL AND SUPPORT SUMMARY OF THE INVENTIONThis invention relates to a chair having a tiltable seat and moreparticularly to a chair seat tilt control and support, more commonlyreferred to as a chair iron. Specifically, the invention is concernedwith a chair control and support for providing an adjustable degree ofbackward tilt to a chair seat assembly wherein the magnitude of the tiltand the ease with which the tilting movement is effected, is readilyadjustable by the occupant of the chair by means of a simple singlemanually controlled member. An essential feature of the inventionresides in the design of the mechanism wherein it may be used with achair seat height adjusting member which permits the chair seat to pivotor turn horizontally relative to the chair base, as well as with a chairseat height adjustable support member not incorporating this feature.

Additionally, the chair control embodiment of this invention isadaptable for use with chairs having a back assembly integrally fonnedwith, rigidly attached to, the seat assembly or with chairs designed andconstructed with an independent mechanism for providing controlled backassembly tilt movement.

In contrast to the chair support and control mechanisms of known designwhich, for the most part, are of heavy cast iron construction,complicated in design, expensive, and limited for use with a specifictype of chair furniture, the chair control of this invention isdistinguished by its relatively simple design, economic and fool-proofconstruction and broad application to a wide variety of chair designs.

Accordingly, among the objects of this invention is a chair control andsupport mechanism which permits of convenient and economicalmanufacture, which combines simple design features with great strength,and which lends itself to be utilized with a wide variety of chairdesigns.

A more specific object of the invention is improvement in known chaircontrols of the prior art in regard to strength and price and in regardto simplicity of design and of manufacturing and assembly procedures.

A feature of the invention resides in the compactness of the structurewherein fewer and less complicated parts are employed than are found incomparable chair controls of the prior art.

An important feature of the invention is the uniform, yieldablyrestraining action of the chair control mechanism to safely andcomfortably provided a tilting movement for the chair seat assembly asit is urged by the occupant from a horizontal position to a comfortablebackward tilt rest attitude.

Another feature of the invention involves the design of the spring andthe spring compression adjustment control whereby selective adjustmentof the yieldable restraint to backward tilt of the chair seat isattained by a minimal amount of torque applied to a hand-manipulatedspindle.

Still another feature of the invention resides in the provision of aresilient, adjustable member to limit the backward tilt of the chairseat and, in cooperation with the compression spring, to bring the chairseat to a safe, cushioned stop from its backward tilt motion.

Additionally, the invention features a chair tilt control mechanismwhich has the distinct advantage of versatile utility of use with achair of the type with back and seat portions rigidly attached and whichmove together as a unit into the tilt position or with a chair whereinthe back portion is independently tilt-adjustable.

Finally, the chair control mechanism of this invention is equallyadaptable to a chair with or without a revolving seat relative to thebase and to chairs with or without independent seat height adjustments.

Briefly stated, the objects of this invention are accomplished with asimplified construction which has for its essential elements a bracketdesigned to be attached to under side of a chair seat and pivotlyengaged to the depending flanges of 75 portions 18A of the bracket 18and the downturned side pora substantially horizontal'plate which isrigidly mounted on a vertical support post. An adjustable compressionspring acting between the bracket and the plate yieldably opposes thetilting movement of the bracket about the pivotal axis whereby a safe,limited degree of chairseat tilt is effected.

These and further objects, features, and advantages of this inventionwill become more fully apparent from or be disclosed in the followingdetailed description of the construction when taken in considerationwith the figures of the drawing wherein like reference characters areemployed to designate like parts in the specification and throughout theseveral views.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation of thechair control and support mechanism shown supporting a chair seatassembly in the nontilt position and illustrating the method of mountingthe chair control and support device on a vertical adjustablepost'supported by the chair base.

FIG. 2 is an end elevation view of the chair control and supportmechanism of FIG. 1 as viewed from the rear of the chair (not shown).

FIG. 3 is a side elevation view of the chair control and supportmechanism of FIG. 2 shown in the tilted position partly-in section.

FIG. 4 is an enlarged view of the compression spring assembly.

FIG. 5 is an enlarged sectional view of the engagement of the plate withthe vertical post.

FIG. 6 is an enlarged view of a pivotal axis arrangement detailing thebushing construction and assembly.

FIG. 7 is an enlarged rear view of a portion of the chair control andsupport illustrating the adjustable screw stop assembly partly insection.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, a chairseat assembly 10 is supported by a chair control and support mechanism14 mounted to the top of a vertical post 16 rising from and supported bya chair pedestal base 12.

The chair control and support mechanism 14, as shown, is comprised of abracket 18 secured, as by means of screws or other suitable fasteningmeans to the underside of the chair seat assembly 10. The bracket 18 isformed of a single sheetof metal so as to have downturned side portions18A and is drilled with a suitable number of spaced apertures in its websection 188 to accommodate the screws, bolts or other suitable means forattachment to the under side of the seat assembly. The downturned sideportions of the bracket serve to greatly increase the structuralstrength of the bracket member and are configurated to accommodate abolt 20 which extends horizontally between and through the downturnedside portions 18A beneath and transverse to the web section 18B of thebracket 18 and is disposed adjacent the vertical post 16.

A plate member 22, also formed from a single sheet of metal and alsohaving downturned side portions 22A, is positioned in spaced relationwithin and beneath the bracket 18. As shown in FIG. 2, the plate 22 hasa configuration similar to that of the bracket 18 but has smallerdimensions whereby a clearance is provided between each of the outersurfaces of the downturned side portions 22A of the plate 22 and each ofthe inner surfaces of the downturned portions 18A of the overlyingbracket member 18.

The bolt 20 which extends horizontally through the downturned sideportions 18A of the bracket 18 also extends through the downturned sideportions 22A of the plate 22 and effects a pivotal engagement of thebracket with the plate.

FIG. 6 depicts the manner in which the two bushings 24 of nylon, orsimilar compressive material nor requiring lubrication, about which thebolt 20 is joumaled, are employed to maintain the space relationshipbetween the downturned side tions 22A of the plate 22. The shank 24A ofeach of the bushings is tightly fitted into the aperture in the plateand the disengagement of the bolt caused by tilting motion of thebracket which could occur if a threadably engaged nut were used.

The apertures in the side portions of the bracket and the apertures inthe side portions of the plate for accommodating the bolt are positionedandaligned to provide a space relation between the web of the plate 228and the bracket web portion 188 in the general area above the pivotalaxis, thus permitting the bracket tilting movement about the the bolt 20as' is best illustrated in FIG.

Again referring to FIG. 1, the plate 22 is shown mounted on the top ofthe vertical post 16 at an acute angle with the horizontal. Preferablythe plate is mounted on the vertical post so as to have an angle ofapproximately 8 10 with the horizontal. As shown in FIG. 1, the webportion of the plateand the web portion of the bracket distal from thepivotal axis converge when the chair seat is in the non-tiltingposition. As may readily be seen, the arrangement effects a slightbackward pitch to the bracket (and the chair seat) and positions thechair seat with a comfortable forward incline of about 4-5 when in thenon-tilting position.

As shown (FIGS. 1 and 3), the pivotal engagement of the bracket 18 andthe plate 22 is immediately rearward of the vertical post 16. Thisarrangement provides optimal structural strength to the mechanism whenthe chair is occupied and is in an operative tilting position (FIG. 3)due to the fact the occupant load forces, which are borne by the pivotalaxis, are translated to the vertical post with a minimum of angularforce resolution form the downward vertical direction.

Since the pivotal axis is not in true vertical alignment with thevertical post 16, a certain amount of torque or bending moment isexperienced by the plate 22. As shown in FIG. 5, a structural stableengagement of the plate with the vertical post is effected toaccommodate any operative bending moment of the plate, thereby assuringa sturdy and safe mechanism. The plate 22, as shown in FIG. 5, ispierced and broached to receive the vertical post 16 in a press fit andthe connection of the plate to the vertical post is further strengthenedwith a circumferential fillet weld 28 about the post and the collar 30formed by the downward extending metal of the broached late 22.

p As illustrated in FIGS. 1 and 3, the portion of the plate to the rearof the pivotal axis is of shorter length than the bracket to allow forthe desired full operative tilting movement of the bracket. As shown inFIG. 7, an adjustable screw 32 with a cap 34 of resilient rubber-likematerial is threadably engaged to the plate 22 for limiting the backwardtilting movement of the bracket 18 by making contact with the bracketweb 188 at the extreme backward tilt position of the bracket, thusaffording a cushioned stop for the bracket (and the chair seat assemblyattached thereto).

Preferably, the bracket of the chair control and support mechanism hasabout a 14 angle of tilt relative to the horizontal when it contacts thecap 34 of the adjustable screw 32 threadably engaged to the plate. Asmay readily be observed, however, a larger or smaller angle of tilt ofthe bracket may be effected by a suitable adjustment of the screw.Alternatively, in place of the adjustable screw, a fixed bumper ofresilient rubber-like material attached to the plate (or bracket) can beused to limit the backward tilt of the bracket and bring the bracket toa cushioned stop.

Resilient means are incorporated in the structure of the invention andarranged so as to react between the fixed plate member 22 and thebracket member 18 to oppose the tilting movement of the bracket. Asshown in FIGS, 1 and 3, a helical pivotal axis defined by spring 36having a frustoconical configuration is positioned beneath the fixedplate 22 adjacent to the forward end of the plate 22C. One end of thespring 36 is compressively engaged with the underside of the plate 22and the lower end of the springis retained by a spindle 38 which isthreadably engaged to the lower end of abolt 40 anchored to the bracketI8 and extending axially through the spring whereby the spring urges theforward portion of the plate and the bracket into a contact relationshipand opposes a tilting motion of the bracket relative to the fixed plate.

As illustrated in better detail in FIG. 3, the bolt 40 slidably extendsthrough a slot in the plate and through a circular hole in the bracketand is anchored to the bracket by means of a short cross bar member 42welded to the upper end of the bolt. A shallow slot or indentation 18Cin the upper surface of the bracket confonning to the cross bar 42geometry is provided to retain the short cross bar and thus prevent thebolt 40 from turning whenthe spindle is manipulated to adjust the springcompression.

' The frustoconical formation of the helical compression spring 36permits the spring to nest when the chair seat (and the bracket) istilted backward and thus the-use of a shorter length of compressionspring can be employed than if the spring had a helical formation ofuniform diameter throughout. Additionally, the frustoconicalconfiguration of the spring permits the use of a smaller diameterspindle collar 38A to retain thespring and thus minimizes the contactarea of spring with spindle assembly. This arrangement produces smallfrictional forces which facilitate operation of the spindle by requiringa relative small amount of torque to bring about the selected degree ofspring compression for selecting the desired amount of biasing forceopposing the tilting motion.

A safety feature of considerable importance is incorporated in thestructure of this invention by having the bolt 40 securing the spring 36and to which the spindle 38 is threadably engaged, swaged to prevent thespindle from being removed from the end of the bolt.

A bumper 44 of resilient material is interposed between the forwardportion of the bracket 18D and the forward portion of the plate 22C(FIG. 3) in order to prevent metal to metal contact when the bracket isin the non-tilt position. The bumper serves to dampen or cushion thebracket stop against the forward portion of the plate as the chair seatis returned from a tilt position by the action of the compressionspring.

The construction of the chair control and support is such that it may beplated with facility if desired, unlike items of the prior art whosedesign was such that it was practically impossible to plate. Plating, ofcourse, would add not only to the attractiveness but also the longevityof the chair control.

The chair control and support of this invention is shown in thepreferred embodiment mounted on a vertical post whichis both heightadjustable and which provides a swivel action to the chair control andsupport. Understandably, the chair control and support may be mounted onany convenient mechanism, such as a vertical post, which is not heightadjustable and/or not rotated.

Recapitulating, the structural embodiment of the inventionadvantageously maximizes the functional capabilities of a select limitednumber of components to effect a unique chair control and support whichhas the attributes of more efiective and safer utility, greaterversatility, and lower cost when compared to chair irons of knowndesign.

While the foregoing has illustrated and described what is nowcontemplated to be the best mode of carrying out the invention, theconstructions are, of course, subject to modification without departingfrom the spirit and scope of the invention. Therefore, it is not desiredto restrict the invention to the particular forms of constructionillustrated and described, but to cover all modifications that may fallwithin the scope of the appended claims.

What is claimed is:

1. In a chair having a base, a vertical post supported by said base anda seat assembly, a chair control and support mechanism comprising;

a. A bracket secured to the underside of said seat assembly,

b. a plate rigidly mounted on the top of the vertical post forsupporting said bracket, said plate and said bracket each fonned of asingle sheet of metal downtumed side portrons,

c. a horizontal pivot bolt extending through the downtumed side portionsof said bracket and the downtumed side portions of said plate rearwardlyof said vertical post and defining a pivot axis for achieving relativetilting movement between said bracket and said plate, and

d. resilient compressible means acting between said bracket and saidplate to yieldably resist said tilting movement.

2. The invention of claim 1 wherein the plate rigidly mounted on the topof the vertical post has an angle of tilt of about 4 8 with thehorizontal whereby the forward end of the plate is higher in elevationthan the rear portion of the plate.

3. The invention 0 claim 1 wherein the cap of the screw threadablyengaged to the web of the plate rearwardly of the vertical post acts asa stop to limit the backward tilting movement of the bracket secured tothe underside of the seat assembly.

4. The invention of claim 1 wherein a bumper of resilient materialmounted on the underside of the web portion of the bracket contacts theweb portion of the plate to the rear of the vertical post mounting so asto limit the backward tilting movement of the bracket secured to theunderside of the seat assembly.

5. The invention of claim 1 wherein the resilient compressible meansacting between said bracket and said plate comprises a helical springhaving a frustoconical configuration, the end of the spring having thelarger diameter compressively the spring having the larger diametercompressively engaged to the bottom surface of the web portion of theplate forward of the vertical post mounting, and the end of the springhaving a smaller diameter retained by a spindle threadably engaged to abolt, said bolt passing axially through the spring, the plate, andanchored to the bracket.

6. The invention of claim 1 wherein a bumper of resilient materialinterposed between the web portion of the bracket and the web portion ofthe plate forward of the vertical post mounting acts to cushion thebracket stop against the plate as the chair seat is returned from thetilt position by the action of the compression spring.

1. In a chair having a base, a vertical post supported by said base anda seat assembly, a chair control and support mechanism comprising; a. Abracket secured to the underside of said seat assembly, b. a platerigidly mounted on the top of the vertical post for supporting saidbracket, said plate and said bracket each formed of a single sheet ofmetal downturned side portions, c. a horizontal pivot bolt extendingthrough the downturned side portions of said bracket and the downturnedside portions of said plate rearwardly of said vertical post anddefining a pivot axis for achieving relative tilting movement betweensaid bracket and said plate, and d. resilient compressible means actingbetween said bracket and said plate to yieldably resist said tiltingmovement.
 2. The invention of claim 1 wherein the plate rigidly mountedon the top of the vertical post has an angle of tilt of about 4* -8*with the horizontal whereby the forward end of the plate is higher inelevation than the rear portion of the plate.
 3. The invention of claim1 wherein the cap of the screw threadably engaged to the web of theplate rearwardly of the vertical post acts as a stop to limit thebackward tilting movement of the bracket secured to the underside of theseat assembly.
 4. The invention of claim 1 wherein a bumper of resilientmaterial mounted on the underside of the web portion of the bracketcontacts the web portion of the plate to the rear of the vertical postmounting so as to limit the backward tilting movement of the bracketsecured to the underside of the seat assembly.
 5. The invention of claim1 wherein the resilient compressible means acting between said bracketand said plate comprises a helical spring having a frustoconicalconfiguration, the end of the spring having the larger diametercompressively the spring having the larger diameter compressivelyengaged to the bottom surface of the web portion of the plate forward ofthe vertical post mounting, and the end of the spring having a smallerdiameter retained by a spindle threadably engaged to a bolt, said boltpassing axially through the spring, the plate, and anchored to thebracket.
 6. The invention of claim 1 wherein a bumper of resilientmaterial interposed between the web portion of the bracket and the webportion of the plate forward of the vertical post mounting acts tocushion the bracket stop against the plate as the chair seat is returnedfrom the tilt position by the action of the compression spring.